Fix setting `logging_level` in Optimiser and LoggingAdapter

Created by: gkirgizov

There're several small tasks:

Allow setting logging_level in Optimiser through API -- currently Optimiser.log is always constructed with default logging level (INFO)
It appears that logging_level in default_log() doesn't do anything, because only arguments from the first initialization are considered. I made a reproducing test in fix-765-attempt branch.
Fixing this issue will allow fixing #765 (closed): it will be enough to disable logging in optimiser (and, hence, disabling tqdm in optimiser.optimise) to avoid the bug. The failing tests are:

=========================== short test summary info ============================
FAILED test/unit/remote/test_remote_composer.py::test_pseudo_remote_composer_classification
FAILED test/unit/remote/test_remote_composer.py::test_pseudo_remote_composer_ts_forecasting
FAILED test/unit/tasks/test_custom.py::test_custom_graph_opt - ValueError: I/...
FAILED test/unit/tasks/test_regression.py::test_multi_target_regression_composing_correct
FAILED test/unit/utilities/test_project_import_export.py::test_export_import_api_correctly
FAILED test/unit/validation/test_table_cv.py::test_composer_with_cv_optimization_correct
FAILED test/unit/validation/test_table_cv.py::test_cv_api_correct - ValueErro...
FAILED test/unit/validation/test_time_series_cv.py::test_composer_cv_correct
FAILED test/unit/validation/test_time_series_cv.py::test_api_cv_correct - Val...
=========== 9 failed, 605 passed, 1567 warnings in 299.57s (0:04:59) ===========

I propose to continue the fix in the branch fix-765-attempt